Create an error message list in the Web application. Is it necessary to create an error number for each error?

Refer to the error message definition in TFs.

Http://msdn2.microsoft.com/en-US/library/aa337645 (vs.80). aspx
Visual Studio team system
Error and event messages in team Foundation

Team Foundation displays error and event messages to inform you of successful and unsuccessful operations. A subset of the error and event messages have been assigned unique ID numbers in the form tfnnnnn.

Numbered error and event messages

Tf10001: The team Foundation server name is not present in configuration file. Contact your team Foundation server administrator.
Tf10002: source control is unable to determine the SID for User name: {0 }.
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